Dry deflocculated body and method of preparing same.



STATES PATENT OFFICE.

CLINTON PAUL TOWNSEND, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR TO ACHESON OILDAG COMPANY, OF NIAGARA FALLS, NEW YORK, A CORPORATION OF NEW YORK.

DRY DEILOGGULATED BODY AND METHOD OF PREPARING SAME.

Specification of Letters Patent.

No Drawing. Application filed January 18, 1910, Serial No. 538,708. Renewed March 23, 1914. Serial Patented Nov. 10, 1914.

To all whom it may concern g Be it lmown that I, CLINTON PAUL Town- SEND, a citizen of the United States, residing at Washington, in the District of ,Columb1a,

' have invented certain new and useful Imexample graphite, lampblaclf," amorphous alumma, etc., may be appropriate treatment in presence of aqueous solutions of certain organic substances capable of exerting a modifying eifect, and particularly vegetable extracts, tannin, or mixtures containing the same, be reduced to such state of subdivision as to be capable of indefinite suspension 1n .water and other liquids, passing readil in this suspended state through the finest ter paper. In this state the bodies are said to be deflocculated. Such aqueous suspensions have the property, in common with the socalled colloidal solutions, of being more or less sensitive to the action of electrolytes, as for example solutions of salts or. mineral acids, being susceptible of flocculation and precipitation thereby. The precipitates so produced are not again directly suspensible in.pure water; that is to say the precipitation of such suspensions is not what is commonly known as a reversible process or .reaction. Similarly, a dry mass prepared by evaporation of the water at normal or higher temperatures cannot be again directly suspended in water.-

I have discovered that under certain conditions it is possible to precipitate the deflocculated body, in such manner that the precipitate, either before or after complete or substantially complete dehydration and separation of theprecipitating reagent, is

again directly suspensible in pure water;

or in other words, that under pro er condi- It)ions the precipitation may be ma e reversile. s i The following is an illustrative example of a procedure 1n accordance with the present invention, although it should be understood that the invention is not restricted to the treatment of graphite, /or to the use of the particular reagents or roportions mentioned .by way of examp e, or to the described manipulations.

Graphite or other suitable material is deflocculated by the action of tannin or equivalent reagent in accordance with any of the methods heretofore used, as for example those of the patents above referred to, or U. S. patent to E. G. Acheson, No. 964,478, patented July 19, 1910. The immediate product is a stiff paste which commonly .con-

tains in admixture with the deflocculated; body a greater or less proportion of nudeflocculated material. The paste is then stirred into sufficient water to suspend the deflocculated material, and this suspension is permitted to stand for several hours or days, or until that portion of the charge which has not undergone deflocculation has settled. The liquid carrying the suspended solid is then removed,.pr'eferably by decanta-tion. This suspension may then be directly treated by'the addition thereto of a reagent capable of precipitating the suspended body in reversible state, by which is meant in such state that the precipitate may be again suspended in water, and when so suspended will exhibit the distinctive characteristics of deflocculated bodies remaining suspended for prolonged or indefinite periods, passing through filter paper, etc. The preferred reagents are pure or commercial acetone, ethyl alcohol, methyl alcohol, and mixtures consisting of or containing these. Other neutral, liquids which are miscible with or soluble in water ma produce equivalent efiects. Preferably volatile liquids are used in order that they may be economically recovered. For example, the a .ueous suspension containing defiocculate graphite may be mixed with an equal or somewhat greater volume of the reagent for example commercial acetone, and ermitted to stand for some hours or until t e precipitate has settled. The supernatant liquid, consisting essentially of the diluted reagent, is then at once removed by decantation or filtration, and the precipitate collected upon a filter,

for example an ordinary filter-press. The

' to possess in the case of graphite the known tion or on the filter with the concentrated or 7 commercial reagent until the water is completely) or substantially eliminated. It may then e further treated, either at atmospheric or somewhat higher temperatures,-

sive temperatures. The resulting product, in

case graphite has been treated is a moderately hard and brittle mass which acquires luster when rubbed, appearing nevertheless to be completely deflocculated in the sense that it is directly suspensible in water without further treatment. It possesses the distinc'tive characteristic of being suspensible in water even without the necessity of being ground to a paste or state of fine subdivision. This characteristic is readily evidenced by placing a fragment of the material prepared as above described in the center ofa dro of water ona glass surface, without stirring, when the fragment will be observed to swell and disintegrate, and to become suspended in the form of extremely minute particles. When distributed through the water by stirring it remains suspended therein for prolonged and so far as now known indefinite periods, passes through filter'paper, is found lubricating properties of the deflocculated suspension, and in eneral exhibits the salient properties of t e original deflocculated material. Dry deflocculated graphite thus prepared does not readily become directly suspended in oil, but oil suspensions thereof may be prepared from the aqueous paste, for example by the method described in U. S. Patent 911,358, granted February 2, 1909, to E. G. Acheson. The dry material appears to be quite stable in presence of air and moisture and is readily stored and transported in sealed packages without special precautions. v

The original suspension, prepared for the purpose of separating any foreign or undefiocculated material, should be as concentrated as is practicablein order to reduce the quantity of preci itant required; and this quantity maybe rther diminished by boiling off a portion of the water, preferably in vacuo or under diminished pressure from the deflocculated suspension, after it has been separated from the sediment, while avoiding any drying of the mass to a nonsuspensible" or irreversible state. The diluted acetone, alcohol or equivalent reagent separated fr'om theprecipitate is readily recovered by fractionating by known methods and may be usedrepeatedly. Inasmuch as the presence of a moderate proportion of water in the precipitating reagent is not material, the fractionations may be so conducted that the recovery of'the bodies as volatile plete, asi e from such losses as are incident to all commercial processes of this kind. The reagent used for washing theprecipitate may be re-used one or more times without re-distillation.

The term dry as herein used is intended to indicate that the precipitate is apparently or physically dry, and not that. no moisture whatever is retained therein, it being well understood that most solid bodies in porous or finely-subdivided form retain appreciable and often considerable proportions of moisture.

In the operation of defiocculating such aphite b the action of tannin or equiva ent modi ying agent, it is observed that the modifying agent disappears from solution, apparently becom'm associated or fixed in or upon the particles of graphite. It is observed that little or none of this tannin is dissolved or extracted by the subsequent treatments as herein described, althou h both acetone and alcohol are solvents o tannin in its usual state. The modifying agent appears" to remain in association with the. material, presumably as a superficial coating upon the constituent particles, and to be'persistently retained thereby. It is probable that the presence of this modifying agent in the dry deflocculated material is connected with its above- .mentioned property of disintegration in presence of water.

The rapidity with which disinte ation occurs may vary considerably according to the reagent used, the manner of preparm the original suspension and the details 0 the treatment. It has been observed in some cases that the material precipitated by methyl alcohol is less readily sus ended thaw that prepared by the action of acetone or ethyl alcohol, and also. that a prolonged treatment with the volatile reagent tends to yield a harder mass which is less quickly responsive to the action of water. 7

Lampblack and the various known forms of carbon-black, treated as above described, form excellent bases for the preparation of printing inks, india ink, etc. These ma be compressed into cakes orsticks, using i desired suitable binding agents, the binder or adhesive being preferably dissolved in acetone, alcohol, glycerin or other non-aqueous solvent. Similarly, the process may be applied to other amorphous pigments, and in general to such materials as'are capable of undergoing deflocculation through the action of organic modifying agents.

I claim: i a

1. As a new article of manufacture, a dry defiocculated body characterized by the property of disintegrating in resence of water and of remaining suspended therein.

2. As a new article of manufacture, dry

precipitant is substantially comdeflocculated aphite characterized by the property of isintegrating in resenee of water and of remaining suspen ed therein.

3. The method of treating aqueous suspensions of deflocculated bodies which consists in precipitating the body 1n reversible state, and vcollecting the precipitate.

4. The method of treating aqueous suspensions of deflocculated bodies which-consists in precipitating the bod lnlreversible state by means of a volatile quid reagent. miscible with water, and collecting the precipitate.

5. The method of treating aqueous suspensions of deflocculated bodies, which consists in precipitating the body in reversible state by means of a volatile liquid reagent miscible with water, washing the precipitate with the liquid reagent, and drying the pre- 20 cipitate.

7. The method of treating aqueous suspen- 25 sions of deflocculated graphite, which con: sists in precipitatingthe gra bite in revers1- 'ble state b -means of a v0 atile liquid reagent miscible with water, washingthe precipitate with the liquid reagent, and drying .30

the precipitate. I

In testimony whereof I aflix my signature presence voftwo witnesses CLINTON PAUL TOWNSEND.

Witnesses J. H. 'Bmoxnns'mm,

NrP. Lnommn. 

